Thursday, April 2, 2015
Saturday, May 22, 2010
Scratches
OK, on topic. Wide belt sanding on wood.
How does this look to you?
Of course everyone wants the best finish scratch they can get, and while many things can affect the aesthetics of the scratch, the scratch pattern is only changed when sanded by a physically different head, such as a drum head or a pad head. The depth of scratch on a steel drum head will be deeper than a soft rubber one, but the pattern will be the same.
Ok. Now that I've lost everybody, including myself....
As I've said before, one of the biggest reasons sanding wood well is so difficult, is something I like to call "subjective quality". What I mean by this is that the surface finish I like may be absolutely terrible to a coworker of mine, and vice versa. "How does this look?", is a question that I avoid when I can while discussing sanding and finishing with customers and clients of mine, not because I don't want to answer it, it is because I can't.
Why, you ask? It seems like a pretty innocuous point. "Do you like this finish?" Simple yes or simple no would do. It's not that I don't have an opinion. Opinions flow from me like......well I don't know, everything I can think of is gross, but trust me, 99% of the time, I have absolutely no problem expressing my opinion to anyone that will listen. Grrrrr....back on topic. Simple question, right?
Not so much. I can only answer this question if I am either a person about to buy this product, whatever it may be, or I am the manager or owner in charge of making these products for myself or to sell to others.
Not Quality, Quantity!
What I strive to do for my customers is to help them achieve the finish they want but even more importantly, I help them maintain that desired finish on every part, every day.
I cannot stress more the importance of the sentence above. It is relatively easy to get one of your cabinet doors, or conference tables, or office desks, or modesty panels perfect. The key is to be able to maintain that finish and color with perfect consistency, regardless of who is running the machines that produce that finish. Consistent quality is the goal.
2 Kinds of Manufacturers in the Wood Industry 1. Manufacturers that Make but don't Finish
One crucial factor of the subjective quality to the finish that is often overlooked on your product should be profitability. Many of the shops and factories I consult with strive valiantly to get the smoothest, glossiest, most perfect finish they can achieve. These perfect finishes, whiles very aesthetically pleasing, may not be the most profitable to the company, especially if you are a company that doesn't put the stain and lacquer on that fantastic finish. A great example of this occurring is in the engineered wood industry, at the the veneered particle board, MDF, or plywood manufacturer. Most of these factories are either buying or making their own veneer faces, pressing them onto the substrate, sanding the panels to a P150, P180 or P220 grit finish, and packaging them for transport to many, many distributors and manufacturers of fine furniture, cabinets, architectural millwork, etc. Here they are routed or cut to proper size and then sanded again prior to finishing. (See my "pre-sanded wood" blog entry.)
While it is understood that the panel manufacturer strives to sell the best quality panel they can, and that part of that process is removing layers of veneer tape, minor handling damage, and many other things, do they really need to sand to such a fine finish? Wouldn't a P80 or P100 finish work just as well as, if not better than the grit sequence normally used? The goal for the panel manufacturing industry shouldn't be the finish quality of the veneer face. These resources would be better utilized concentrating on substrate thickness tolerances, proper substrate densities, proper veneer face adhesion, etc.
I shouldn't pick on the panel plants specifically, because everything I mentioned above is applicable to any manufacturer of any component made from wood that sands their product but doesn't apply the final finish to it themselves. Scratch pattern shouldn't really be all that important to your final product.
I have two quick questions for you:
1. Wouldn't your customers choose to have thicker veneer/wood than a better finish from your industry? (not that your customers ever have to do rework!)
2. How much money could you save on abrasives if you only sanded to P120 instead of P220?
2. Manufacturers that Finish what they Make
I guess I'd like to start out with a quick question. What is the first thing your customer looks at?
Normally the answer to this is either design, or finish.
Design? Can't help you there. I have about as much imagination as does my new daughter, and she drools.
Finish. Here is where I might be able to find a couple pennies here and there. I'll be back next week with the conclusion to this post. (I've determined that if I want to carry on with this, it has to be when the wife is at the store AND the baby is sleeping, or at 3:00 in the morning.)
I think I just heard the garage door.........Hi honey..........of course, I'd LOVE to see your new nail polish........
Wednesday, September 30, 2009
New Seminar @ MATC
If the response is over what can be handled, we will plan on having another. Here is a run down of the topics:
Madison Area Technical College
Patrick Molzahn
Stiles Machinery
Peter Van Dyke
October 27, 2009
- Sanding – Basic Principles
- Why do we sand?
Dimension
Flatten surface
Create desired surface (scratch pattern)
Clean up surface
Edge breaking
Preparation for finishing
First step in finishing not the last step in manufacturing
Preparation between finish coats
Prepare for Polishing for high gloss finishes
P2000 grits and higher
- What do we sand?
Raw lumber
Glued up blanks
Panel core
MDF
Partical board
Plywood
Stave core (glued up lumber blocks)
Mineral core
Veneer
Unsanded
Presanded
Tape
Reconstituted veneer (man made – office furniture)
Sketch faces
Exposed wood bands
Mouldings
S4S Lumber
Raised panels
Assemblies
5 piece doors
Face frames
Doors
Windows
Sealer
High gloss finishes
- How do we sand?
The cutting tool – 10 minutes
Abrasive types
Backings
Types of coatings
Treatments
Stock removal
Scratch depth
Sanding methods include pro’s & con’s of each)- Everything from Hand Sanding to Robotic Sanding
- Sanding defects
- Machine demonstrations
- Questions
From the looks of it, this will be an all encompassing seminar on many different types of sanding, hopefully to get the finish you need.
Friday, September 18, 2009
Powder Coating
I stopped at a company today to provide possible automatic surface preparation solutions for a company that has, in my humble opinion, nearly perfected this technology. There product has the best finish I have seen yet. They also had a full range of finishes from textured to high gloss.
If this is something you've been looking for on any of your design projects large or small, this company is somebody that should definitely be looked at.
The company's name is BTD Wood Powder Coating Inc. in Brainerd, MN. A good point of contact there is Mr. Achim Burgardt.
This is only just a little unsolicited information because I was so impressed. Extremely well done.
The sky is definitely the limit on this process. I can't wait to see what comes next.
Thursday, September 3, 2009
"Pre-sanded Wood"
HMM...."I don't need a multiple head sander. I bring all my product in pre-sanded."
Head Scratch..."We just touch these up by hand. They all come in pre-sanded."
Call 911..."Our company sands our veneered particle board sheets to 220 grit before we ship them. Our customers pay a premium for the convenience of not sanding them again. The parts they make from my sheets are ready to go straight to finishing."
Although I am paraphrasing these statements, they are entirely too common. The three examples above are kind of a poor, poorer, and poorest comments I hear almost daily.
I'll explain them all in a little greater detail in a bit, but first I would like to cover a few things that often get overlooked.

Why do we sand anything? What is my goal pertaining to the surfaces of my workpieces?
When I ask the first question, 9 out of 10 people will give me part of the right answer. "Too make the surface smooth."
Correct........kind of.
Actually, we need to sand the surfaces of the wood for another reason, just as important. We can demonstrate this with a simple procedure some of you may have heard of. It is commonly referred to as The Water Drop Test.

Source: Douglas J Gardner "The Relevance of Surface Properties & Wood Finishes to the Wood Science & Technology Research Community“
The above picture shows the differences in wettability on a piece of yellow birch. The two arrows are pointing to the inactive and activated surfaces. The test has three drops of water placed on the surface at the same time. The drops above were photographed after 30 seconds. The drop on the left has kept its large contact angle with the unsanded wood surface. The surface under the middle drop was sanded with 2 passes of 220 grit sandpaper, you can see that the wettability is much improved. The last drop has almost completely soaked into the surface. The wettability is even more improved on this surface due to 5 passes of 220 grit sandpaper.
The best write-up I've seen written is published in the book "The Encyclopedia of Wood" - by the U.S. Department of Agriculture. Chapter 9 is the relevant portion of the book.
In a nutshell, when you sand the surface of the wood, not only are you making the surface smooth, but are also reactivating it. Extractives from within the wood cause a poor wettability seen by the left hand drop. These "extractives" mainly come to the surface of the wood from either heat, such as when the part is in a press, but also with time. This is why we have 2 very important thumbrules in the sanding world. The first is that all wood should be sanded no greater than 24 hours before it is finished and sealed. The second is that when sanding veneer, it should be the goal of the operator to remove about 1/2 the thickness of the veneer. Some woods are more alkaline, while some are more acidic. This is also affected by sanding the surface. Whether it be adhesive or stain or polyurethane, sanding the surface allows the bond to be formed not only mechanically but also chemically.
So, the problem with the first statement is that normally the grit I need to use to uncover a raw, active wood surface is not the final scratch pattern I want. If I do use my finishing grit on one head with one pass, I will either prematurely load the belt, or I won't take enough stock off and my surface will be blotchy. Below are three pictures at the cellular level of wood. One is normal, and 2 are shown crushed by using a dull or loaded sanding belt.



How well do you think the wood from that third picture finishes? Not good.
Monday, July 27, 2009
Oops
Sunday, July 19, 2009
Brush Sanding
This is a tooling issue, not a sanding issue. Our next step here is to bring in a router tooling expert to work with me on getting perfect product to their membrane presses. The most important thing to remember about a brush sander is that it is for scratch pattern, not stock removal.
Sunday, July 12, 2009
Miscellaneous Links
Here is a general brush sanding article from ISW Online: http://tinyurl.com/mtvpy5
Here is a webinar that I authored and gave last year. I will be giving another on Brush Sanding after the Las Vegas show. Sometime in the beginning of August. Please let me know if you are interested in attending.
Please look for the article 06/08. Thanks.
http://tinyurl.com/n96j4k
Thursday, July 2, 2009
5 Piece Doors - Part 1




Wednesday, June 24, 2009
Dressing your machine's conveyor belt
Saturday, June 20, 2009
Select Veneer
http://www.sawdustsoup.com/profiles/blogs/manufacturing-efficiency-and
Thursday, June 18, 2009
Discussion on chatter marks and critical maintenance.
http://tinyurl.com/l52zgc
Very cool place to hang out for woodworkers
http://www.sawdustsoup.com/
Check it out....they have their own blog, forums, photo albums, etc. all in one spot. Lots of valuable information there.
Wednesday, June 17, 2009
NeoCon 09 Impressions
The booths and showrooms were stunning as usual, even if they were a little less extravagant than years past.
Trends
Here are some of the trends in design that I noticed in most of the booths and showrooms.
Reconstituted Veneer (Recon) - Nearly all of the largest furniture manufacturers had at least 1 or more office unit, desk, or conference table done with recon. While recon is fairly common in some sectors of the woodworking industry, and even some sectors of the office furniture industry, this was the first time that I've seen this used so widely. I don't know if this is just a new design trend, or they are subliminally sending a message to the wood industry about prices, it looks like we will be seeing more recon for the near future. People like TreeFrog should be very happy with that. Sanding and finishing recon is unlike sanding some cherry veneer. It is quite hard actually, due to the amount of glue. The important thing to accomplish when sanding it is to ensure the veneer is flat. You will have to use a cross-belt (preferred) or a soft, large diameter rubber drum to get this done correctly. If not, it becomes extremely hard to sand the sealer coat evenly without burning through the high spots.
Bamboo - It seemed as if this was everywhere. This has been popular as flooring, of course, for years, but I saw it used as wall coverings, the decoration in pressed acrylic or resin walls, veneer for desks and conference tables, and even the chairs. This material is a very good choice for many applications due to its hardness and resistance to wear. When calibrating bamboo for thickness, I usually drop down a grit from where I would normally start my sequence because of this hardness. Although not as oily, the wood this grass is most like is teak.
High Gloss - Like bamboo, this application is always at the show, but usually you see it mainly on solid surface, stone, and painted wood (MDF) surfaces. This year most of the vendors had at least one collection done to a mirror finish. This is pretty standard fare in Europe, but it seems to be migrating west. All of the vendors had exceptional high gloss finishes, but I have to note that The Mayline Group had a collection, manufactured and imported from China, that was so perfect, it took them awhile to convince me it was really veneer and not laminate. The reflections on the surface of the desk were not the least bit distorted. When sanding high gloss, the best option, if available, are cross-belts. They are long which helps dispel heat, they always use a "chevron" or felt strip internal belt which again helps to dispel heat, while keeping the scratch very, very short. This hides most sanding belt defects, and prevents the snake lines that occur when using an normal wide belt pad head. They are also much less expensive that a wide belt of the same grit. Believe me, it is very easy to damage a 9 micron grit belt.
Lastly, I just wanted to say thank you to all who took the time to talk with me at the show. I know how important and valuable your time is. Of special note: Nucraft Furniture, OFS Brands, Haworth Inc., Hon, Gunlocke, Paoli, Steelcase, Herman Miller, Indiana Furniture, Leggett & Platt, Bernhardt, Kimball, The Mayline Group, Knoll, Armstrong, Green Choice Flooring, Legacy, Terrazzo & Marble Supply, 3 Form, Coaster Office, Real Wood Floors, Lumber Liquidators, Schneller, Gianni Inc., Kittinger, Capri Cork, and Avian. If I forgot anyone, sorry, I guess I owe you dinner, your choice of venue.
P.S. Please remember this is only a small humble view of an incredibly large show. Please feel free to correct anything I may have wrong. Also, my opinions, not my employers. Thanks.
Monday, June 15, 2009
NeoCon 09
Friday, June 12, 2009
Amazing Furniture
Welcome to Villa Reale! ... http://link.gs/0qzx
Wednesday, June 10, 2009
High Gloss
This is a video of a very small company in Germany that manufactures brilliant automatic high gloss machines. The parts need to be sanded to a very fine grit and then inserted into the machine for polishing. This machine was made with wood in mind, but has been successfuly used on plastics, solid surface, some stone/concrete.
The company's name is Bauerrichter, and is privately owned.
Please let me know what you think in the comments section or on Twitter @SandingMan.
Tuesday, June 9, 2009
Heesemann's New Automatic Orbital
Here is a picture of Heesemann's new automatic orbital head from the Ligna show. What follows is a functional description of the process this head uses to remove cross-grain scratches without leaving swirls. (I get somewhat technical and dry.....sorry.) Let me know if you have any questions.
Functional Description of the Principles of the Heesemann OSR-Units
OSR = Orbital Scratch Removal. Drawing 1 shows the basic principle of a simple orbital sander. A pressure beam equipped with abrasive paper is supported by two eccentric bearings on a fixed frame. The eccentric bearings bring the frame into an orbital motion (picture 1). Individual sanding grains on the abrasive paper move on a circular path with the radius of the eccentric bearings. When a workpiece passes the abrasive belt moving in that way, protruding sanding grains will mark individual areas. These sanding lines are similar to the ones shown in picture 2. Even though there are no visible sanding lines only in longitudinal direction, as after wide belt sanding, these sanding marks are clearly visible. They are often called "swirls". Existing orbital sanders try to wipe out these "swirls" by an additional motion overlapping the rotating-swiveling pressure beam. The most common way to achieve a favorable effect is to overlap a second rotary motion. This figure is more complicated; therefore, we show here a motion transverse to the feed direction. This is shown in picture 3. You can see that the swirls on the workpiece surface are overlapping and are somewhat cancelled out. Basically, what the OSR-system has tried to do is to avoid the development of swirls altogether. The sanding paper is pressed down from the inside by a lamella system (photograph 1). It is motor driven back and forth transverse to the feed direction at varying speeds depending upon application. Pictures 4 to 6 schematically describe that constantly new areas of the oscillating abrasive paper are pressed down. This avoids the development of the characteristic marks (swirls) so that they do not have to be wiped out. The result is a high-quality surface without annoying sanding lines. An additional advantage is that a bearing system of high-quality and lasting liability can be used because of the simple orbital motion.
Maintenance Class Timeline
One note about the maintenance class is that I only do this at my facility because we actually tear down components of the machine in addition to putting real mechanical and electrical faults in the sander. I think it would be bad if I broke the machine at your facility and not be able to fix the problem.
Comments?
SA550 “Heesemann Belt Sander Maintenance”
DAY 1
8:00 - 8:30 Orientation & Welcome
8:30 – 9:30 Wide Belt Sander Nomenclature
Major Machine Parts
- Contact Roller
- Combi-head
- Segmented Pad
- Pressure Rollers/Shoes
- Graphite/Felt Pad
- Wide Belt/Cross Belt
- Planer Head
- Orbital Head
- Controller
- Electrical Cabinet
Sequence of Machine Operation
Sanding Applications
- Solid Wood
- Veneer
- Sealer
9:30 – 10:00 Abrasive Belt Technology
Wide Belt Abrasive Technology
Types of Abrasives
Grit Designation
Backing Material & Splices
Storage & Handling
10:00 - 10:15 Break
10:15 - 11:30 Sander Set-Up & Operations (Hands-on)
- Mounting Sanding Belts
- Machine Adjustments
- Pre-Settings
- Thickness Settings
- Sanding Belt Speed
- Feed Speeds
- Selection of Activated Heads
11:30 - 12:15 Lunch
12:15 - 3:15 Conveyor Belt Maintenance
Daily Maintenance
Dressing
- With Contact Roller
Ø Precautions
Ø Dress Board Dimensions and Placement
Ø Grit Selection
Ø Procedure
- Without Contact Roller
Ø Precautions
Ø Dress Roller alignment and installation
Ø Grit Selection
Ø Procedure
Bed Removal for Belt Replacement
- Removal Procedure
- Replacement Procedure
3:15 – 3:30 Afternoon Break
3:30 – 4:00 Poly V-Belt Tensioning & Replacement
- Troubleshooting and Replacement
- Installation Procedure
4:00 – 4:30 Wide Belt Sander Safety
Guarding
Belt Condition
Dust Collection
Sparking
DAY 2
8:00 - 8:30 Review & Questions
8:30 – 9:30 Contact Roller Maintenance
Daily Maintenance
Operation and Setup
Dressing
9:30 – 9:45 Morning Break
9:45 – 10:45 Contact Roller Maintenance (cont’d)
Alignment Procedure
10:45 – 11:30 Segmented Pad Maintenance
Daily Maintenance
Operation and Setup
Platen
Repair
Replacement
11:30 - 12:15 Lunch
12:15 – 1:00 Segmented Pad Maintenance (cont’d)
Alignment Procedure
Diagnostics
1:00 – 3:00 Sanding Defects & Troubleshooting
Identification
- Dubbing
- Rounded Edges
- Sand Through
- Snake Lines
- Shadows
- Zig-zag Lines
- Chatter Marks
- Splice Marks
- Polishing
- Dull and Worn Belts
- Burn Marks
- Stock
- Controller & Machine Adjustments
- Sanding Belts
- Others
Corrective Actions
3:00 – 3:15 Afternoon Break
3:15 – 4:30 Controller Vibrations
Machine parameters
Controller screen
Diagnostics
Basic Operations
DAY 3
8:00 - 8:30 Review & Questions
8:30 - 10:30 Machine Controller (hands-on)
Basic Operations
Fault Diagnosis
Machine parameters and their effect
10:30 – 10:45 Morning Break
10:45 – 11:30 Reading Heesemann Schematics
Symbols
Manual Schematic Drawings
11:30 – 12:15 Lunch
12:15 – 3:00 Electrical Troubleshooting (hands-on)
Component Locations
Electrical Cabinet Layout
Real Fault Troubleshooting
3:00 – 3:10 Afternoon Break
3:10 – 4:15 Specific Maintenance
Ordering Parts
Cleaning Machine
Using External Computer
4:15 – 4:45 Conclusion, Exam & Course Evaluation







